MOSCOW—Syrian President Bashar Assad says his government has agreed to surrender its chemical weapons in response to Russia's initiative and not because of the U.S. threat of attack.

Assad told Russia's state Rossiya 24 news channel in an interview that is set to be broadcast fully later Thursday that "Syria is transferring chemical weapons under international control because of Russia."

He added that "the U.S. threats hadn't influenced" his government's decision.

Russia on Monday proposed that Syria place its chemical weapons under international control and eventually dismantle them to avert a U.S. strike, and Syria quickly accepted the proposal.

U.S. Secretary of State John Kerry and his Russian counterpart Sergey Lavrov are set to sit down together to discuss details of the plan in Geneva on Thursday.